Magnetic head with assisted magnetic recording and method of making thereof

ABSTRACT

A magnetic head includes a main pole configured to serve as a first electrode, an upper pole containing a trailing magnetic shield configured to a serve as a second electrode, and an electrically conductive portion located in a trailing gap between the main pole and the trailing magnetic shield. The electrically conductive portion is not part of a spin torque oscillator stack, and the electrically conductive portion includes at least one electrically conductive, non-magnetic material layer. The main pole and the trailing magnetic shield are electrically shorted by the electrically conductive portion across the trailing gap between the main pole and the trailing magnetic shield such that an electrically conductive path is present between the main pole and the trailing magnetic shield through the electrically conductive portion.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims benefit of U.S. Provisional Patent ApplicationSer. No. 62/743,110, filed Oct. 9, 2018, which is herein incorporated byreference.

FIELD

The present disclosure relates generally to the field of magneticrecording heads, and particular to assisted magnetic recording.

BACKGROUND

Disk drives comprise a disk and a head connected to a distal end of anactuator arm which is rotated about a pivot by a voice coil motor (VCM)to position the head radially over the disk. The disk comprises aplurality of radially spaced, concentric tracks for recording user datasectors and servo sectors. The servo sectors comprise head positioninginformation (e.g., a track address) which is read by the head andprocessed by a servo control system to control the actuator arm as itseeks from track to track.

FIG. 1 shows a prior art disk 902 comprising a number of servo tracks904 defined by servo sectors 906 ₀-906 _(N) recorded around thecircumference of each servo track. Each servo sector 906 _(i) comprisesa preamble 908 for storing a periodic pattern, which allows proper gainadjustment and timing synchronization of the read signal, and a syncmark 910 for storing a special pattern used to symbol synchronize to aservo data field 912. The servo data field 912 stores coarse headpositioning information, such as a servo track address, used to positionthe head over a target data track during a seek operation. Each servosector 906 _(i) further comprises groups of servo bursts 914 (e.g., Nand Q servo bursts), which are recorded with a predetermined phaserelative to one another and relative to the servo track centerlines. Thephase based servo bursts 914 provide fine head position information usedfor centerline tracking while accessing a data track during write/readoperations. A position error signal (PES) is generated by reading theservo bursts 914, wherein the PES represents a measured position of thehead relative to a centerline of a target servo track. A servocontroller processes the PES to generate a control signal applied to ahead actuator (e.g., a voice coil motor) in order to actuate the headradially over the disk in a direction that reduces the PES.

FIG. 2A illustrates a conventional disk drive 810 used for data storage.A disk media (i.e., a magnetic disk) 850 is attached to a spindle motorand hub 820. The spindle motor and hub 820 rotate the media 850 in adirection shown by arrow 855. A head stack assembly (HSA) 815 includes acarriage 820 and a voice coil motor (VCM) 825. A first end of anactuator arm 870 is supported by the carriage 820. A second end of theactuator arm 870 supports a head-gimbal assembly (HGA) 830. The HSA 815positions the actuator arm 870 using the voice coil motor (VCM) 825 anda pivot shaft and bearing assembly 860 over a desired data track 840 ofthe disk media 850 to read and/or write data from and/or to the datatrack 840.

FIG. 2B illustrates the details of the HGA 830 located over the datatrack 840. The HGA 830 includes a slider 880 located above the datatrack 840 and a magnetic head 600 (also called a recording head or areading and recording head) located on the slider 880. The magnetic head600 contains a recording head (also called a magnetic recordingtransducer, a writing head or a writer) 660. The magnetic head 600 mayalso contain a reading head (also called a magnetic reading transducer,a reading element or a reader) 610. The media 850 and the track 840 moveunder the slider 880 in a down-track direction shown by arrow 842. Thecross-track direction is shown by arrow 841. The recording head 660 hasa leading edge 891 and a trailing edge 892. In this embodiment, thetrailing edge 892 of the recording head 660 is the final portion of therecording head 660 that writes (i.e., records) data onto the data track840 as the media 850 moves under the slider 880 in the down-trackdirection 842.

FIG. 3 illustrates a side view of the disk drive 810 shown in FIG. 2A.At least one disk media 850 (e.g., plural disk media 850) are mountedonto the spindle motor and hub 820. The HSA 815 supports at least oneactuator arm 870 (e.g., plural arms 870). Each actuator arm 870 carriesa suspension 875 and the slider 880. The slider 880 has an air bearingsurface (ABS) facing the media 850. When the media 850 is rotating andthe actuator arm 870 is positioned over the media 850, the slider 880slides above the media 850 by aerodynamic pressure created between theslider ABS and the surface of media 850.

Data is typically written to the disk by modulating a write current inan inductive coil to record magnetic transitions onto the disk surfacein a process referred to as saturation recording. During readback, themagnetic transitions are sensed by a read head and the resulting readsignal demodulated by a suitable read channel. However, as conventionalperpendicular magnetic recording (PMR) approaches its limit, furthergrowth of the areal recording density becomes increasingly challenging.

SUMMARY

According to an aspect of the present disclosure, a magnetic headincludes a main pole configured to serve as a first electrode, an upperpole containing a trailing magnetic shield configured to a serve as asecond electrode, and an electrically conductive portion located in atrailing gap between the main pole and the trailing magnetic shield. Theelectrically conductive portion is not part of a spin torque oscillatorstack, and the electrically conductive portion comprises at least oneelectrically conductive, non-magnetic material layer. The main pole andthe trailing magnetic shield are electrically shorted by theelectrically conductive portion across the trailing gap between the mainpole and the trailing magnetic shield such that an electricallyconductive path is present between the main pole and the trailingmagnetic shield through the electrically conductive portion.

According to another aspect of the present disclosure, a method ofoperating a magnetic recording head comprises providing a currentbetween a main pole and an upper pole containing a trailing magneticshield through an electrically conductive portion located in a trailinggap between the main pole and the trailing shield while applying amagnetic field to the main pole from a coil to record data to a magneticdisk. The electrically conductive portion is not part of a spin torqueoscillator stack, and the electrically conductive portion comprises atleast one electrically conductive, non-magnetic material layer.

According to yet another aspect of the present disclosure, a method offorming a magnetic head comprises forming a main pole over a substrate,forming an electrically conductive, non-magnetic material layer over themain pole, forming a trailing magnetic shield directly on a trailingsidewall of the electrically conductive, non-magnetic material layer,and forming an air bearing surface (ABS) of the magnetic head by lappingportions of the main pole and the trailing magnetic shield. Anelectrically conductive path is present between the main pole and thetrailing magnetic shield through the electrically conductive,non-magnetic material layer.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a top view of prior art disk including a plurality of servotracks defined by servo sectors.

FIG. 2A illustrates a top view of a conventional hard disk drive andFIG. 2B schematically illustrates a top view of a head-gimbal assemblyof the hard disk drive of FIG. 2A.

FIG. 3 illustrates a side view of the conventional hard disk drive ofFIG. 2A.

FIG. 4 is an in-track vertical cross-sectional view of an exemplarymagnetic head of the present disclosure.

FIG. 5A is an in-track vertical cross-sectional view of a firstexemplary recording head according to a first embodiment of the presentdisclosure.

FIG. 5B is an air bearing surface (ABS) view of a portion of the firstexemplary recording head according to the first embodiment of thepresent disclosure.

FIG. 6 is an in-track vertical cross-sectional view of a secondexemplary recording head according to a second embodiment of the presentdisclosure.

FIG. 7A is an in-track vertical cross-sectional view of a thirdexemplary recording head according to a third embodiment of the presentdisclosure.

FIG. 7B is an ABS view of a portion of the third exemplary recordinghead according to the third embodiment of the present disclosure.

FIGS. 8A-8F are sequential vertical cross-sectional views of a firstexemplary structure for manufacture of the first exemplary recordinghead according to the first embodiment of the present disclosure.

FIGS. 9A-9E are sequential vertical cross-sectional views of a secondexemplary structure for manufacture of the second exemplary recordinghead according to the second embodiment of the present disclosure.

FIGS. 10A-10C are sequential vertical cross-sectional views of a thirdexemplary structure for manufacture of the third exemplary recordinghead according to the third embodiment of the present disclosure.

FIG. 11 shows magnetization M, bias current I, and the current inducedAmpere's field in the main pole and in the trailing shield in thevicinity of a trailing gap according to an embodiment of the presentdisclosure.

FIG. 12 shows finite element model (FEM) simulation results of the biascurrent distribution and the Ampere's field (MP) produced by 5 mA of thebias current through the main pole according to an embodiment of thepresent disclosure.

DETAILED DESCRIPTION

As discussed above, the present disclosure is directed to magneticrecording heads employing Ampere field enhancement and methods ofmanufacturing such magnetic recording heads.

The drawings are not drawn to scale. Multiple instances of an elementmay be duplicated where a single instance of the element is illustrated,unless absence of duplication of elements is expressly described orclearly indicated otherwise. Ordinals such as “first,” “second,” and“third” are employed merely to identify similar elements, and differentordinals may be employed across the specification and the claims of theinstant disclosure. The same reference numerals refer to the sameelement or similar element. Unless otherwise indicated, elements havingthe same reference numerals are presumed to have the same composition.As used herein, a first element located “on” a second element can belocated on the exterior side of a surface of the second element or onthe interior side of the second element. As used herein, a first elementis located “directly on” a second element if there exist a physicalcontact between a surface of the first element and a surface of thesecond element.

As used herein, a “layer” refers to a material portion including aregion having a thickness. A layer may extend over the entirety of anunderlying or overlying structure, or may have an extent less than theextent of an underlying or overlying structure. Further, a layer may bea region of a homogeneous or inhomogeneous continuous structure that hasa thickness less than the thickness of the continuous structure. Forexample, a layer may be located between any pair of horizontal planesbetween, or at, a top surface and a bottom surface of the continuousstructure. A layer may extend horizontally, vertically, and/or along atapered surface. A substrate may be a layer, may include one or morelayers therein, or may have one or more layer thereupon, thereabove,and/or therebelow.

As used herein, an “electrically conductive material” refers to amaterial having electrical conductivity greater than 1.0×10⁵ S/cm. Asused herein, a “metallic material” refers to a conductive materialincluding at least one metallic element therein. As used herein, an“electrically insulating material” or a “dielectric material” refers toa material having electrical conductivity less than 1.0×10⁻⁶ S/cm. Asused herein, a “semiconducting material” refers to a material havingelectrical conductivity in the range from 1.0×10⁻⁶ S/cm to 1.0×10⁵ S/cm.All measurements for electrical conductivities are made at the standardcondition.

Referring to FIG. 4, an in-track vertical cross-sectional view of anexemplary magnetic head 600 of one embodiment of the present disclosureis illustrated. The magnetic head 600 is configured for magneticrecording employing a spin torque oscillator (STO). The magnetic head600 is positioned over a recording track 840 on a disk media. Themagnetic head 600 comprises, from the leading side of the head (i.e.,the left side of FIG. 4), a reading head 610 and a recording head 660.The reading head comprises a lower reading shield 620, a read sensor 650(i.e., a reading element), and an upper reading shield 690. The readsensor 650 can include a tunnel magnetoresistance (TMR) device, a giantmagnetoresistance (GMR) device, or the like.

The recording head 660 can comprise a record element 200 that includes aspin torque oscillator (STO) element, an optional auxiliary pole 202, amain pole 220, a magnetic coil 225 that is wound around the main pole220, and a trailing shield 280 which may be integrated with an upperpole 285. The record element 200 is formed in a gap between the mainpole 220 and the trailing shield 280. The main pole 220 and trailingshield 280 serve as first and second electrodes for flowing electricalcurrent through the record element 200 during recording (i.e., writing).A bias circuitry 290 can be electrically connected to the main pole 220and the upper pole 285, such as to the end portions of the main pole andthe upper pole 285 distal from the ABS and the record element 200. Thebias circuitry 290 may include a voltage or current source (or aconnection to an external voltage or current source) and one or moreswitching devices, such as transistors or relays which can switch thevoltage or current on and off. The bias circuitry 290 is configured toprovide a current or voltage to the main pole 220 and the upper pole285. For example, the bias circuitry 290 may provide a current betweenthe main pole 220 and the upper pole 285/trailing shield 280 that flowsthrough the record element 200. An insulating material portion 270 isprovided around the magnetic coil 225 between the main pole 220, thetrailing shield 280 and the upper pole 285. An electrically insulatingmaterial layer 272 can be provided between end portions of the main pole220 and the upper pole 285 where the bias circuitry connections (i.e.,electrical contacts 291, 292 attached to the ends of the main pole andupper pole respectively) are made (i.e., distal from the ABS).

During operation of the recording head 660, if perpendicular magneticrecording is employed, a magnetic field emitted from the main pole 220passes through a magnetic recording layer (e.g., hard magnetic layer)710 and a soft magnetic underlayer 720 of the recording track 840 of thedisk media 850, and returns to the auxiliary pole 202. A magnetizationpattern (represented by arrows) is recorded in the magnetic recordinglayer 710. In an implementation of a MAMR system, the magnetizationpattern is recorded when electrical current flows between the main pole210 and the upper pole 285 which is physically and electricallyconnected to trailing shield 280, and, in one embodiment, ahigh-frequency magnetic field from the STO element of the record element200 is applied to the recording track 840 to temporarily reduce thecoercivity of the magnetic recording layer 710.

FIGS. 5A and 5B show magnified views of a first exemplary embodiment ofthe recording head 660 of a system that includes a record element 200according to a first embodiment of the present disclosure. The main pole220 is configured to emit a recording magnetic field for affecting themagnetic medium of the magnetic recording layer 710 (shown in FIG. 4).When electrical current passes through the magnetic coil 225, themagnetic field generated by the electrical current through the magneticcoil 225 magnetizes the soft magnetic material of the main pole 220, andthe magnetic field is guided by through the main pole 220 and thetrailing shield 280 to complete a magnetic loop.

As shown in FIG. 5B, the record element 200 includes a spin torqueoscillator (STO) stack 250 located on a trailing sidewall of the mainpole 220 in a gap between the main pole and the trailing shield. Sidemagnetic shields (also known as wrap around shield, WAS) 206 can beprovided around the main pole 220 without physically contacting the mainpole 220. A gap 205 which can be filled with a non-magnetic material,such as a dielectric material, for example aluminum oxide, is providedbetween the main pole 220 and each of the seed layer 207 and the sidemagnetic shields 206. The side magnetic shields 206 can be provided onthe sides of the main pole 220, and may contact an electricallyconductive seed layer 207 and the trailing shield 280. The trailingshield 280 is a magnetic shield located on a trailing sidewall of thespin torque oscillator 250 stack.

The main pole 220 is configured to serve as a first electrode of anelectrical circuit, and the trailing shield 280 is configured to serveas a second electrode of the electrical circuit. The electrical circuitis biased by the bias circuitry 290, which is configured to provideelectrical current between the main pole 220 and the trailing shield280/upper pole 285 through the record element 200 in two oppositedirections, which correspond to the two opposite magnetizationdirections that the record element 200 can induce in the magnetic mediumto be recorded. An air bearing surface (ABS) of the magnetic head 600includes planar surfaces of the main pole 220, the spin torqueoscillator 250, and the magnetic shield as embodied as the trailingshield 280. Thus, the spin torque oscillator is exposed to the ABS. Theplanar surfaces can be within a same two-dimensional plane that providedby lapping during a manufacturing process.

As shown in the inset in FIG. 5A, according to an aspect of the presentdisclosure, a first electrically conductive path ECP1 is present throughthe spin torque oscillator 250 stack between the first electrode (asembodied as the main pole 220) and the second electrode (as embodied asthe trailing shield 280). A second electrically conductive path ECP2 ina parallel connection with the first electrically conductive path ECP1is present between the first electrode and the second electrode througha conductive material portion 360. Preferably but not necessarily, theconductive material portion 360 includes an electrically conductive,non-magnetic metal or a non-magnetic metallic alloy. In one embodiment,the conductive material portion 360 does not include a material thatgenerates an alternating magnetic field upon application of anelectrical current therethrough.

In one embodiment, the conductive material portion 360 is located in thegap between the main pole 220 and the trailing shield 280. In oneembodiment, the conductive material portion 360 is not exposed to theABS and is spaced from the ABS by a portion of the trailing shield 280and or by the STO 250. In one embodiment, the conductive materialportion 360 contacts a leading surface of the trailing shield 280. Inone embodiment, the conductive material portion 360 includes anon-magnetic electrically conductive material, which can be anon-magnetic metal such as copper, tungsten, ruthenium, chromium and/orany other non-magnetic metal or a non-magnetic metallic alloy.

In one embodiment, a conductive layer stack 350 can also be provided inthe gap between the main pole 220 and the trailing shield 280 within thesecond electrically conductive path ECP2. The conductive layer stack 350can have a same set of component layers as the spin torque oscillator250 stack, and can be spaced from the spin torque oscillator 250 stackby a dielectric spacer 310. The dielectric spacer 310 includes adielectric material such as aluminum oxide, silicon oxide, and/orsilicon nitride, and prevents the conductive layer stack 350 fromfunctioning as another spin torque oscillator stack. In one embodiment,the conductive material portion 360 causes a predominant portion of themagnetic flux through the main pole 220 to flow through the spin torqueoscillator 250 stack, and significantly reduces the magnetic fluxthrough the conductive layer stack 350. For this reason, spin torqueeffect in the conductive layer stack 350 is much less than the spintorque effect in the spin torque oscillator 250 stack.

In one embodiment, the conductive layer stack 350 and the spin torqueoscillator 250 stack can be located directly on the trailing sidewall ofthe main pole 220 in the trailing gap 222 between the main pole and thetrailing shield 280. The conductive material portion 360 can be locatedon a trailing sidewall of the conductive layer stack 350. In oneembodiment, an interface between the spin torque oscillator 250 stackand the magnetic shield (as embodied as the trailing shield 280) can bewithin a same plane as an interface between the conductive layer stack350 and the conductive material portion 360.

Referring to the inset in FIG. 5A, the main pole 220 can have a trailingedge taper such that the trailing edge of the main pole and the trailinggap 222 between the main pole 220 and the trailing shield 280 can betapered (i.e., slanted) in a non-perpendicular direction compared to theABS. For example, the trailing edge of the main pole 220 and thetrailing gap 222 can extend in a direction which is inclined withrespect to the plane of the ABS by an angle of 10 to 80 degrees, such as30 to 60 degrees. The trailing shield 280 can have a “bump” structure ata throat portion which results in the narrowing of the trailing gap 222adjacent to the ABS where the STO 250 is located. The bump structurewhich defines a short effective trailing shield throat height (eTH) thatmay range from 20 nm to 150 nm. The shortest dimension in the directioninto the air bearing surface (ABS) that determines the current path canbe defined by either the eTH (if the bump material is non-conducting),or back edge position of the conducting trailing gap (if it is patternedand shorter than eTH), or both (if the two coincide).

Above the STO 250 and above the bump in the trailing shield 280, thetrailing gap 222 is wider (i.e., has a larger width) than the width ofthe trailing gap 222 adjacent to the bump (i.e., the throat portion) ofthe trailing shield 280. The conductive layer stack 350 and theconductive material portion 360 are located in the wider portions of thetrailing gap 222 above the throat portion of the trailing shield 280while the STO 250 stack is located adjacent to the throat portion of thetrailing shield in the narrower portion of the trailing gap 222. Thus,the conductive layer stack 350 and the conductive material portion 360electrically short the main pole 220 and the trailing shield 280 acrossthe trailing gap 222.

The electrical bias circuitry 290 is configured to flow electricalcurrent between the first electrode (embodied as the main pole 220) andthe second electrode (embodied as the trailing shield 280) through thefirst electrically conductive path ECP1 and the second electricallyconductive path ECP2 in a forward direction and in a reverse directiondepending on selection of a bias direction by the switching elements ofthe electrical bias circuitry 290.

In one embodiment, the spin torque oscillator 250 stack is configured togenerate a high-frequency magnetic field which is superimposed with therecording magnetic field to record data to the magnetic medium whencurrent flows through the first and second electrically conductive paths(ECP1, ECP2). The spin torque oscillator 250 stack can include anymaterial layer stack that is effective for the purpose of generating thehigh-frequency magnetic field for superposition with the recordingmagnetic field. The combination of the high-frequency magnetic fieldwith the recording magnetic field lowers the coercivity of the magneticmedium on a disk during the recording process.

In an illustrative example shown in FIG. 5B, the spin torque oscillator250 stack can include a stack, from the side of the leading edge to theside of the trailing edge, an electrically conductive, non-magnetic seedlayer 252, a spin polarized layer 256 that generates precession ofmagnetization during operation, a non-magnetic electrically conductivespacer layer 256, and an optional magnetic field generating layer 258.In an illustrative example, the non-magnetic conductive seed layer 252can include a non-magnetic conductive material such as Cr, Ru, W, andCu, the spin polarized layer can include a magnetic nickel-iron alloy,the non-magnetic conductive spacer layer 256 can include a non-magneticconductive material such as Cu, and the optional field generating layer258, if present, can include another magnetic nickel-iron alloy. If thefield generating layer 258 is present, then another optionalnon-magnetic, electrically conductive spacer layer (e.g., copper spacerlayer) may be located between layer 258 and the trailing shield 280.

The thickness of the non-magnetic conductive seed layer 252 can be in arange from 3 nm to 12 nm, although lesser and greater thicknesses canalso be employed. The thickness of the spin polarized layer 256 can bein a range from 3 nm to 12 nm, although lesser and greater thicknessescan also be employed. The frequency of the magnetic field generated bythe spin polarized layer 256 can be in a range from 10 GHz to 40 GHz,although lesser and greater frequencies can be employed. The magnitudeof the magnetic field generated by the spin polarized layer 256 can bein a range from 250 Gauss to 1,000 Gauss, although lesser and greatermagnitudes can be employed for the magnetic field. The thickness of thenon-magnetic conductive spacer layer 256 may be in a range from 3 nm to15 nm, although lesser and greater thicknesses can also be employed. Thethickness of the field generating layer 258, if present, may be in arange from 3 nm to 12 nm, although lesser and greater thicknesses canalso be employed. Additional layers may be optionally employed toenhance performance of the spin torque oscillator 250 stack.

FIG. 6 shows magnified views of a second exemplary embodiment of arecording head 660 that includes a record element 200 according to asecond embodiment of the present disclosure. The recording head 660illustrated in FIG. 6 can be derived from the recording head 660illustrated in FIGS. 5A and 5B by modifying the record element 200.

The recording head 660 of the second exemplary embodiment is the same asthe recording head 660 of the first exemplary embodiment, except thatthe conductive layer stack 350 is replaced by a first conductivematerial portion 340, and the dielectric spacer 310 may be omitted. Allother components of the recording head 660 of the second exemplaryembodiment are the same as those of the recording head 660 of the firstexemplary embodiment and will not be repeated herein for brevity.

The first conductive material portion 340 is provided within the secondelectrically conductive path ECP2. The first conductive material portion340 is not exposed to the ABS and is spaced from the ABS by the spintorque oscillator 250 stack and/or the throat portion of the trailingshield 280. Preferably but not necessarily, the first conductivematerial portion 340 includes an electrically conductive non-magneticmetal (e.g., copper) or a non-magnetic metallic alloy. Alternatively,the first conductive material portion 340 can include a conductivemultilayer stack of non-magnetic layers. In one embodiment, the firstconductive material portion 340 does not include a material thatgenerates an alternating magnetic field upon application of anelectrical current therethrough.

In one embodiment, the first conductive material portion 340 contactsthe trailing sidewall of the main pole 220 and a rear sidewall of thespin torque oscillator 250 stack that is located on an opposite side ofthe STO 250 stack from the ABS. The second conductive material portion360 can be located on a trailing sidewall of the first conductivematerial portion 340 and contact the trailing shield 280. Thus, thefirst and the second conductive material portions 340, 360 electricallyshort the main pole 220 to the trailing shield 280. In one embodiment,an interface between the spin torque oscillator 250 stack and thetrailing shield 280 can be within the same plane as an interface betweenthe first conductive material portion 340 and the second conductivematerial portion 360. In one embodiment, the first conductive materialportion 340 and the spin torque oscillator 250 stack can be locateddirectly on the trailing sidewall of the main pole 220. The STO 250stack is located in the trailing gap 222 adjacent to the throat portionof the trailing shield 280, while the first and the second conductivematerial portions 340, 360 are not exposed to the ABS and are located inthe wider portion of the gap above the throat portion of the trailingshield 280.

The electrical bias circuitry 290 is configured to flow electricalcurrent between the first electrode (embodied as the main pole 220) andthe second electrode (embodied as the trailing shield 280/upper pole285) through the first electrically conductive path ECP1 and the secondelectrically conductive path ECP2 in a forward direction and in areverse direction depending on selection of a bias direction. The spintorque oscillator 250 stack can have the same configuration as, andprovide the same function as, in the first embodiment.

In an alternative embodiment, first and the second conductive materialportions 340, 360 may be replaced by single electrically conductive,non-magnetic layer, such as copper. Thus, a single electricallyconductive, non-magnetic layer may be located in the trailing gap 222 inaddition to the STO 250.

FIGS. 7A and 7B show magnified views of a third exemplary embodiment ofa recording head 660 that includes a conductive material portion 360 asa read element according to a third embodiment of the presentdisclosure. The recording head 660 illustrated in FIGS. 7A and 7B can bederived from the recording head 660 illustrated in FIGS. 5A and 5B bymodifying the record element 200.

The recording head 660 of the third exemplary embodiment is the same asthe recording head 660 of the first exemplary embodiment, except thatthe STO 250 and the conductive layer stack 350 are replaced by aconductive material portion 360, and the dielectric spacer 310 may beomitted. All other components of the recording head 660 of the secondexemplary embodiment are the same as those of the recording head 660 ofthe first exemplary embodiment and will not be repeated herein forbrevity.

Preferably but not necessarily, the conductive material portion 360includes at least one electrically conductive, non-magnetic materiallayer, such as at least one metal (e.g., copper, gold, platinum,ruthenium, chromium or tungsten) layer or a non-magnetic metallic alloylayer, such as a single electrically conductive non-magnetic materiallayer. Alternatively, the conductive material portion 360 can include aconductive multilayer stack of non-magnetic layers, or a multilayerstack of electrically conductive, magnetic and non-magnetic layers. Inone embodiment, the conductive material portion 360 does not include amaterial that generates an alternating magnetic field upon applicationof an electrical current therethrough.

The record element 200 can consist of only the conductive layer 360,which is located on a trailing sidewall of the main pole 220. Sidemagnetic shields 206 can be provided around the main pole 220 tipwithout physically contacting the main pole 220 as illustrated in FIG.7B. The side magnetic shields 206 can be provided on the sides of themain pole 220, and may contact the seed layer 207 and the trailingshield 280. A gap 205 filled with a dielectric is provided between themain pole 220 and each of the seed layer 207 and the side magneticshields 206. The trailing shield 280 is a magnetic shield located on atrailing sidewall of the spin torque oscillator 250 stack.

The main pole 220 is configured to serve as a first electrode of anelectrical circuit, and the trailing shield 280 is configured to serveas a second electrode of the electrical circuit. The electrical circuitis biased by the bias circuitry 290, which is configured to provideelectrical current through the main pole 220 and the trailing shield280/upper pole 285 in two opposite directions, which correspond to thetwo opposite magnetization directions that the record element 200 caninduce in the magnetic medium to be recorded. An air bearing surface(ABS) of the magnetic head 600 includes planar surfaces of the main pole220, the conductive material portion (e.g., the non-magnetic conductivelayer) 360, and the trailing shield 280. Thus, in this embodiment, theconductive material portion 360 is exposed to the ABS. The planarsurfaces can be within a same two-dimensional plane that provided bylapping during a manufacturing process. In one embodiment, theconductive layer 360 located in the trailing gap 222 contacts thetrailing sidewall of the main pole 220 and a leading sidewall oftrailing shield 280 to electrically short them.

According to an aspect of the present disclosure, an electricallyconductive path ECP is present through the conductive layer 360 betweenthe first electrode (as embodied as the main pole 220) and the secondelectrode (as embodied as the trailing shield 280). The electrical biascircuitry 290 is configured to flow electrical current between the firstelectrode (embodied as the main pole 220) and the second electrode(embodied as the trailing shield 280) through the electricallyconductive path ECP in a forward direction and in a reverse directiondepending on selection of a bias direction.

In one embodiment, a distal end of the main pole 220 and a distal end ofthe trailing magnetic shield 280, can be located on an opposite side ofthe air bearing surface ABS. The distal end of the main pole 220 whichis connected to one electrical contact 291 can be an end portion of thefirst electrode the electrical bias circuitry 290, and the distal end ofthe trailing shield 280 which is connected to another electrical contact292 of the electrical bias circuitry 290 can be an end portion of thesecond electrode. The electrically conductive path ECP through theconductive layer 360 (i.e., through the record element 200 whichconsists of only layer 360) can be the only path that provideselectrical conduction between the distal end of the main pole 220 andthe distal end of the trailing magnetic shield 280 for conduction ofelectrical current through the main pole. In one embodiment, anelectrically insulating material layer 272 can provide physicalisolation and electrical isolation between the distal end of the mainpole 220 and the distal end of the upper pole 285.

The record element 200 of the first, second and/or third embodiments maybe incorporated into the magnetic head 600 shown in FIG. 4. A magneticstorage device can be provided, which includes the magnetic head 600incorporating the features of the first, second or third exemplaryrecording head 660, the magnetic medium which may be embodied as themagnetic recording layer 710 of the recording track 840 of a disk medium850, a drive mechanism for passing the magnetic medium over the magnetichead 600, and a controller electrically coupled to the magnetic head 600for controlling operation of the magnetic head 600 as illustrated inFIGS. 2 and 3.

FIGS. 8A-8F illustrate a sequence of processing steps that can beemployed to manufacture the first exemplary recording head. Referring toFIG. 8A, an auxiliary pole 202, side magnetic shields 206, and adielectric material filling a portion of the gap 205 between the mainpole 220 and the side magnetic shields 206 (not shown for clarity) areformed over a substrate 300. The main pole 220 is subsequently formedwithin a groove formed in the dielectric material. In one embodiment,the main pole 220 may have a leading edge tapered surface 220A (whichmay be supported by the side magnetic shield 206 and/or by a dielectriclayer, which is not shown for clarity) and a trailing edge taperedsurface 220B. Subsequently, a layer stack of component layers (252, 254,256, 258) for forming a spin torque oscillator stack can be formed on atop (i.e., trailing) surface of the main pole 220, which is a trailingsidewall of the main pole 220. The layer stack may extend over thetrailing edge tapered surface 220B of the main pole (not shown forclarity). Specifically, the non-magnetic conductive seed layer 252, thespin polarized layer 256 that generates precession of magnetizationduring operation, the non-magnetic conductive spacer layer 256, and theoptional field generating layer 258 can be sequentially deposited. Thecomposition and the thickness of the various component layers (252, 254,256, 258) for the spin torque oscillator 250 stack can be as describedabove. The various component layers (252, 254, 256, 258) can be formedby conformal and/or non-conformal deposition process such as chemicalvapor deposition (CVD), atomic layer deposition (ALD), physical vapordeposition (PVD), and/or various plating methods.

Referring to FIG. 8B, the layer stack of component layers (252, 254,256, 258) for forming the spin torque oscillator stack can be patternedby a combination of a lithographic patterning process and an etchprocess. For example, a photoresist layer (not shown) can be appliedover the spin torque oscillator 250 stack, and can be lithographicallypatterned to cover two discrete portions near an edge of the main pole220 that is proximal to the air bearing surface to be subsequentlyformed. The gap between the two discrete portions of the patternedphotoresist layer can have the dimension of the width of the dielectricspacer 310 to be subsequently formed, and may be in a range from 15 nmto 60 nm, although lesser and greater widths can also be employed. Thepattern in the photoresist layer is transferred to through the layerstack of component layers (252, 254, 256, 258) by the etch process. Forexample, an ion milling process that employs the patterned photoresistlayer as an etch mask can be employed to pattern the layer stack ofcomponent layers (252, 254, 256, 258).

A continuous remaining portion of the layer stack of component layers(252, 254, 256, 258) located at the air bearing surface side constitutesthe spin torque oscillator 250 stack, which is a mesa structure. Anothercontinuous remaining portion of the layer stack of component layers(252, 254, 256, 258) located adjacent to the spin torque oscillator 250stack constitutes the conductive layer stack 350, which is another mesastructure. A trench 309 is provided between the spin torque oscillator250 stack and the conductive layer stack 350. A field region 269 isprovided, which includes a physically exposed top surface of the mainpole 220 and is free of remaining portions of the layer stack ofcomponent layers (252, 254, 256, 258). The conductive layer stack 350has a same set of component layers (252, 254, 256, 258) as the spintorque oscillator 250 stack.

Referring to FIG. 8C, a dielectric material can be deposited in thetrench 309 and in the field region 269. Excess portions of thedielectric material can be removed from above the top surfaces of theconductive layer stack 350 and the spin torque oscillator 250 stack by aplanarization process such as chemical mechanical planarization (CMP).The remaining portion of the dielectric material in the trench 309constitutes the dielectric spacer 310. The remaining portion of thedielectric material in the field region 269 constitutes a firstdielectric material portion 270A. The dielectric spacer 310 and thefirst dielectric material portion 270A include a dielectric materialsuch as aluminum oxide, silicon oxide, or silicon nitride. Theconductive layer stack 350 is spaced from the spin torque oscillator 250stack by the dielectric spacer 310.

Referring to FIG. 8D, another dielectric material can be deposited andpatterned to form a second dielectric material portion 270B, which canbe formed directly on the top surface of the first dielectric materialportion 270A. The second dielectric material portion 270B includes adielectric material such as aluminum oxide, silicon oxide, or siliconnitride. The first and second dielectric material portions (270A, 270B)can be components of the insulating material portion 270. Anelectrically conductive, non-magnetic material can be deposited over thetop surface of the conductive layer stack 350. For example, alithographic patterning process can be performed to form a patternedphotoresist layer including an opening within the area of the conductivelayer stack 350. The conductive material can be deposited in the openingin the photoresist layer, and the photoresist layer can be lifted off toform the conductive material portion 360 described above. Alternatively,a non-conductive material layer may be deposited as a continuous layer,and can be patterned by a combination of a lithographic patterningprocess and an etch (e.g., ion milling) process to provide theconductive material portion 360. In this case, the second dielectricmaterial portion 270B can be formed before or after forming theconductive material portion 360. In one embodiment, the conductivematerial portion 360 does not physically contact the spin torqueoscillator 250 stack.

Preferably but not necessarily, the conductive material portion 360includes a non-magnetic metal or a non-magnetic metallic alloy.Alternatively, the conductive material portion 360 can include aconductive multilayer stack of non-magnetic layers. In one embodiment,the conductive material portion 360 does not include a material thatgenerates an alternating magnetic field upon application of anelectrical current therethrough.

In one embodiment, the conductive material portion 360 can have ahomogeneous composition throughout. In one embodiment, the conductivematerial portion 360 can comprise, and/or consist essentially of,copper, tungsten, ruthenium, chromium, and/or any other non-magneticmetal or a non-magnetic metallic alloy. The thickness of the conductivematerial portion 360 can be in a range from 20 nm to 200 nm, althoughlesser and greater thicknesses can also be employed. The conductivematerial portion 360 is formed over the trailing sidewall of the mainpole 220, and directly on a trailing sidewall of the conductive layerstack 350.

Referring to FIG. 8E, the trailing shield 280 (which is a magneticshield located on the side of the trailing sidewall of the spin torqueoscillator 250 stack) can be formed. The trailing shield 280 can beformed directly on the top surfaces (which are trailing sidewalls) ofthe conductive material portion 360 and the spin torque oscillator 250stack by deposition and patterning of a soft magnetic material.Subsequently, additional material layer can be deposited and patternedas needed. For example, components of the magnetic coil 225, additionalportions of the insulating material portion 270 and the upper pole 285can be formed and a recess in a trailing sidewall of the main pole canbe formed by ion milling (not shown for clarity).

Referring to FIG. 8F, an air bearing surface (ABS) of the magnetic head600 can be provided by lapping portions of the main pole 220, the spintorque oscillator 250 stack, and the trailing shield 280. As discussedabove, the first electrically conductive path ECP1 includes the spintorque oscillator 250 stack, and the second electrically conductive pathECP2 includes the conductive layer stack 350 and the conductive materialportion 360.

FIGS. 9A-9E illustrate a sequence of processing steps that can beemployed to manufacture the second exemplary recording head. Referringto FIG. 9A, an exemplary structure that can be employed to form thesecond exemplary recording head is shown, which can be the same as theexemplary structure shown in FIG. 8A.

Referring to FIG. 9B, the layer stack of component layers (252, 254,256, 258) for forming the spin torque oscillator stack can be patternedby a combination of a lithographic patterning process and an etchprocess. For example, a photoresist layer (not shown) can be appliedover the spin torque oscillator 250 stack, and can be lithographicallypatterned to cover a discrete portion near an edge of the main pole 220that is proximal to the air bearing surface to be subsequently formed.The pattern in the photoresist layer is transferred to through the layerstack of component layers (252, 254, 256, 258) by the etch process. Forexample, an ion milling process that employs the patterned photoresistlayer as an etch mask can be employed to pattern the layer stack ofcomponent layers (252, 254, 256, 258). A continuous remaining portion ofthe layer stack of component layers (252, 254, 256, 258) located at theair bearing surface side constitutes the spin torque oscillator 250stack, which is a mesa structure. A field region 269 is provided, whichincludes a physically exposed top surface of the main pole 220 and isfree of remaining portions of the layer stack of component layers (252,254, 256, 258).

Referring to FIG. 9C, a first electrically conductive, non-magneticmaterial can be deposited over a physically exposed top surface of themain pole 220 adjacent to the spin torque oscillator 250 stack. Forexample, a lithographic patterning process can be performed to form apatterned photoresist layer including an opening adjacent to the spintorque oscillator 250 stack. The first conductive material can bedeposited in the opening in the photoresist layer, and the photoresistlayer can be lifted off. The remaining portion of the first conductivematerial constitutes a first conductive material portion 340.Alternatively, the first conductive material layer may be deposited as acontinuous layer, and can be patterned by a combination of alithographic patterning process and an etch (e.g., ion milling) processto provide the first conductive material portion 340.

Preferably, but not necessarily, the first conductive material portion340 includes a non-magnetic metal or a non-magnetic metallic alloy.Alternatively, the first conductive material portion 340 can include aconductive multilayer stack of non-magnetic layers. In one embodiment,the first conductive material portion 340 does not include a materialthat generates an alternating magnetic field upon application of anelectrical current therethrough. In one embodiment, the first conductivematerial layer includes a non-magnetic conductive material such ascopper, ruthenium, chromium, tungsten, another non-magnetic elementalmetal, or a non-magnetic alloy thereof.

In one embodiment, the first conductive material portion 340 can contacta sidewall of the spin torque oscillator 250 stack. In one embodiment,the top surface of the first conductive material portion 340 may beplanarized. In this case, the top surface of the first conductivematerial portion 340 can be coplanar with the top surface of the spintorque oscillator 250 stack. In one embodiment, the first conductivematerial portion 340 can comprise, and/or consist essentially of,copper, tungsten, ruthenium, chromium, and/or any other non-magneticmetal or a non-magnetic metallic alloy. The first conductive materialportion 340 is formed directly on a trailing sidewall of the main pole220.

Referring to FIG. 9D, a dielectric material can be deposited in theregion that is not covered by the spin torque oscillator 250 stack orthe first conductive material portion 340. The dielectric material canbe deposited as a continuous material layer, and excess portions of thedielectric material can be removed from above the first conductivematerial portion 340 and the spin torque oscillator 250 stack by amasked etch process. The remaining portion of the dielectric materialconstitutes a dielectric material portion 270C, which can be a portionof the insulating material portion 270.

A second electrically conductive, non-magnetic material can be depositedon the first conductive material portion 340. For example, alithographic patterning process can be performed to form a patternedphotoresist layer including an opening overlying the first conductivematerial portion 340. The second conductive material can be deposited inthe opening in the photoresist layer, and the photoresist layer can belifted off. The remaining portion of the second conductive materialconstitutes a second conductive material portion 360. Alternatively, thesecond conductive material layer may be deposited as a continuous layer,and can be patterned by a combination of a lithographic patterningprocess and an etch (e.g., ion milling) process to provide the secondconductive material portion 360.

Preferably but not necessarily, the second conductive material portion360 includes a non-magnetic metal or a non-magnetic metallic alloy.Alternatively, the second conductive material portion 360 can include aconductive multilayer stack of non-magnetic layers, or a conductivemultilayer stack of magnetic layers. In one embodiment, the secondconductive material portion 360 does not include a material thatgenerates an alternating magnetic field upon application of anelectrical current therethrough. In one embodiment, the secondconductive material portion 360 includes a non-magnetic conductivematerial such as copper, ruthenium, chromium, tungsten, anothernon-magnetic elemental metal, or a non-magnetic alloy thereof. Thesecond conductive material portion 360 can include the same material as,or a different material from, the first conductive material portion 340.In one embodiment, the second conductive material portion 360 can have ahomogeneous composition throughout. In one embodiment, the secondconductive material portion 360 can comprise, and/or consist essentiallyof, copper, tungsten, ruthenium, chromium, and/or any other non-magneticmetal or a non-magnetic metallic alloy. The thickness of the secondconductive material portion 360 can be in a range from 20 nm to 200 nm,although lesser and greater thicknesses can also be employed. The secondconductive material portion 360 is formed over the main pole 220, anddirectly on a trailing sidewall of the first non-magnetic conductivematerial portion 340.

Referring to FIG. 9E, the trailing shield 280 (which is a magneticshield located on the side of the trailing sidewall of the spin torqueoscillator 250 stack) can be formed. The trailing shield 280 can beformed directly on the top surfaces (which are trailing sidewalls) ofthe conductive material portion 360 and the spin torque oscillator 250stack by deposition and patterning of a soft magnetic material.Subsequently, additional material layers can be deposited and patternedas needed. For example, components of the magnetic coil 225, additionalportions of the insulating material portion 270 and the upper pole 285can be formed and a recess in a trailing sidewall of the main pole canbe formed by ion milling (not shown for clarity).

An air bearing surface (ABS) of the magnetic head 600 can be provided bylapping portions of the main pole 220, the spin torque oscillator 250stack, and the trailing shield 280. As discussed above, the firstelectrically conductive path ECP1 includes the spin torque oscillator250 stack, and the second electrically conductive path ECP2 includes thefirst and second conductive material portions (340, 360).

FIGS. 10A-10C illustrate a sequence of processing steps that can beemployed to manufacture the third exemplary recording head. Referring toFIG. 10A, an auxiliary pole 202, side magnetic shields 206, and adielectric material filling a portion of the gap 205 between the mainpole 220 and the auxiliary pole 202 and the side magnetic shields 206are formed over a substrate (not shown). The main pole 220 issubsequently formed within a groove formed in the dielectric material.

Subsequently, an electrically conductive, non-magnetic material can bedeposited on the air bearing side of the top surface of the main pole220. For example, the conductive material layer may be deposited as acontinuous layer, and can be patterned by a combination of alithographic patterning process and an etch (e.g., ion milling) processto provide a conductive material portion 360. Alternatively, theconductive material portion 360 can be formed by a lift-off process.Preferably but not necessarily, the conductive material portion 360includes a non-magnetic metal or a non-magnetic metallic alloy.Alternatively, the conductive material portion 360 can include aconductive multilayer stack of non-magnetic layers, or a conductivemultilayer stack of magnetic layers. In one embodiment, the conductivematerial portion 360 does not include a material that generates analternating magnetic field upon application of an electrical currenttherethrough. In one embodiment, the conductive material portion 360includes a non-magnetic conductive material such as copper, gold,platinum, ruthenium, chromium, tungsten, another non-magnetic elementalmetal, or a non-magnetic alloy thereof. In one embodiment, theconductive material portion 360 can comprise, and/or consist essentiallyof, copper, gold, platinum, tungsten, ruthenium, chromium, and/or anyother non-magnetic metal or a non-magnetic metallic alloy. Theconductive material portion 360 is formed directly on a trailingsidewall of the main pole 220.

Referring to FIG. 10B, a dielectric material can be deposited in theregion that does not overlap with the conductive material portion 360.The dielectric material can be deposited as a continuous material layer,and excess portions of the dielectric material can be removed from abovethe conductive material portion 360 by a masked etch process.Alternatively, a patterned mask layer including an opening adjacent tothe conductive material portion 360 can be formed. A dielectric materialcan be deposited within the opening, and the patterned mask layer can belifted off. The remaining portion of the dielectric material constitutesa dielectric material portion 270D, which can be a portion of theinsulating material portion 270. The dielectric material portion 270Dincludes a dielectric material such as aluminum oxide, silicon oxide, orsilicon nitride.

Referring to FIG. 10C, the trailing shield 280 (which is a magneticshield located on the side of the trailing sidewall of the spin torqueoscillator 250 stack) can be formed. The trailing shield 280 can beformed directly on the top surface (which is the trailing sidewall) ofthe conductive material portion 360 by deposition and patterning of asoft magnetic material. Subsequently, additional material layers can bedeposited and patterned as needed. For example, components of themagnetic coil 225, additional portions of the insulating materialportion 270 and the upper pole 285 can be formed and a recess in atrailing sidewall of the main pole can be formed by ion milling (notshown for clarity).

An air bearing surface (ABS) of the magnetic head 600 can be provided bylapping portions of the main pole 220, the conductive material portion360, and the magnetic shield (i.e., the trailing shield 280). Asdiscussed above, the electrically conductive path ECP includes themagnetic conductive material portion 360.

The various recording heads of the present disclosure provide advantagesover prior art recording heads by utilizing Ampere's field generated byelectrical current through a conductive material portion 360.Specifically, the electrical current flowing between the main pole 220and the trailing shield 280 generates the Ampere's field, which isemployed to achieve significant areal density capability (ADC) gain. Theareal density capability from the Ampere's field can be significant.

FIG. 11 shows magnetization M, bias current I, and the current inducedAmpere's field in the main pole 220 and in the trailing shield 280 inthe vicinity of a trailing gap 222, which includes the record element200 containing the conductive material portion 360, for the thirdexemplary recording head. The principle of operation illustrated in FIG.11 applies equally to the second electrically conductive path ECP2 ofthe first and second exemplary recording heads.

Referring back to FIGS. 5A, 5B, 6, 7A, and 7B, the main pole 220 and thetrailing magnetic shield 280 can be in direct electric contact throughthe conducting trailing gap 222 containing the record element 200, whichcan consist of the conductive material portion 360 as in the thirdembodiment, or can include the conductive material portion 360 and thespin torque oscillator 250 stack and additional components as in thefirst and second embodiments. The main pole 220 and the trailing shield280 are otherwise electrically insulated and isolated from each other.The main pole 220 constitutes a first electrode and the trailing shield280/upper pole 285 constitutes a second electrode. When an electricalbias voltage is applied across the first and second electrodes,electrical current flows from the main pole 220 into the trailing shield280, or vice versa through the record element 200.

In one embodiment, the insulating material layer 272 can be a thindielectric layer such as an aluminum oxide layer, which is provided inthe back gap area between end portions of the first electrode and thesecond electrode. The insulating material layer 272 can have a thicknessin a range from 10 nm to 100 nm, such as from 20 nm to 50 nm, althoughlesser and greater thicknesses can also be employed. Additionalinsulating material can be provided in order to provide electricalisolation between the first electrode (as embodied as the main pole 220)and the second electrode (as embodied as the trailing shield 280).

During operation of the recording heads of the present disclosure, anelectrical bias voltage is applied across the main pole 220 and thetrailing shield 280. The electrical bias voltage induces electricalcurrent between the main pole 220 and the trailing shield 280. Thiselectrical current improves performance of the recording head with ahigher ADC, as elaborated below. The electrical bias voltage across themain pole 220 and the trailing shield 280 can be a direct current (DC)bias voltage (with either polarity), or can be an alternating current(AC) bias voltage. In the case of an AC bias voltage, it is preferred tohave a waveform that follows the waveform of the write current throughthe magnetic coil 225 per the bits to be written, either in-phase, orout of phase. In other words, an AC bias voltage can be applied as apulse only during the transition in the magnetization during therecording process.

During operation of the recording heads of the present disclosure, anelectric current flows from the main pole 220 into the trailing shield280, or vice versa. As illustrated in FIG. 12, this current produces anAmpere field inside both the main pole 220 and the trailing shield 280,as well as in the recording media. FIG. 12 shows finite element model(FEM) simulation results of the bias current distribution and theAmpere's field (MP) produced by 5 mA of the bias current through themain pole according to an embodiment of the present disclosure. For abias current of 5 mA (which corresponds to a bias voltage of 150 mV anda total resistance of 30 Ohm), a circular field inside the main pole 220is clearly visible, with magnitude of ˜100 Oe at the ABS side, and ˜200Oe in the back, which is consistent with the current densitydistribution (higher in the back and lower at the ABS).

Because of the small dimension defined by the bump position, the highcurrent density is mainly concentrated inside the main pole 220 and thetrailing shield 280 in the vicinity of the trailing gap 222 area, whichis in the range of approximately from 100 nm to 150 nm into the airbearing surface (ABS). According to Ampere's law, this current willproduce a circular magnetic field that is in the direction transverse tothat of the current. Since the current direction is substantially thesame as the direction of the magnetization of the main pole 220 and thetrailing shield 280, this Ampere field is also transverse to themagnetization, thus producing a transverse magnetization component withrespect to the flux flow direction in the main pole 220 and the trailingshield 280 around the trailing gap 222. This will in turn make fasterthe flux reversal in the main pole 220 and trailing shield 280.

In addition to the current induced Ampere field inside the recordinghead that makes the magnetization switching faster, the Ampere fieldalso has other non-limiting benefits. One benefit is that the Amperefield could change the magnetization direction of the main pole and thetrailing shield in the vicinity of the trailing gap, such that the fluxshunt from the main pole 220 into the trailing shield 280 is reduced,leading to higher field (thus higher overwrite) in the media. Anotherbenefit is that the media will also experience this Ampere's field.

Although the foregoing refers to particular preferred embodiments, itwill be understood that the disclosure is not so limited. It will occurto those of ordinary skill in the art that various modifications may bemade to the disclosed embodiments and that such modifications areintended to be within the scope of the disclosure. Where an embodimentemploying a particular structure and/or configuration is illustrated inthe present disclosure, it is understood that the present disclosure maybe practiced with any other compatible structures and/or configurationsthat are functionally equivalent provided that such substitutions arenot explicitly forbidden or otherwise known to be impossible to one ofordinary skill in the art. All of the publications, patent applicationsand patents cited herein are incorporated herein by reference in theirentirety.

What is claimed is:
 1. A magnetic head, comprising: a main poleconfigured to serve as a first electrode; an upper pole comprising atrailing magnetic shield configured to a serve as a second electrode;and an electrically conductive portion comprising a multilayer stacklocated in a trailing gap between the main pole and the trailingmagnetic shield; wherein the electrically conductive portion is not partof a spin torque oscillator stack, and the electrically conductiveportion comprises at least one first layer comprising an electricallyconductive, non-magnetic material and at least one second layercomprising a material different than the at least one first layer,wherein the electrically conductive, non-magnetic material portion isrecessed from an air bearing surface (ABS); and wherein the main poleand the trailing magnetic shield are electrically shorted by the atleast one first layer of the electrically conductive portion across thetrailing gap between the main pole and the trailing magnetic shield suchthat an electrically conductive path is present between the main poleand the trailing magnetic shield through the at least one second layerof the electrically conductive portion.
 2. The magnetic head of claim 1,further comprising: an electrical bias circuitry configured to flowelectrical current between the first electrode and the second electrodethrough the electrically conductive portion; a first electrical contactconnecting a portion of the main pole distant from an air bearingsurface to the electrical bias circuitry; a second electrical contactconnecting a portion of the upper pole distant from the air bearingsurface to the electrical bias circuitry; and an electrically insulatingmaterial layer located between the portions of the main pole and theupper pole distal from the air bearing surface.
 3. The magnetic head ofclaim 2, wherein: the electrically insulating material layer providesphysical and electrical isolation between the portions of the main poleand the upper pole distal from the air bearing surface; and the onlyelectrically conductive path between the main pole and the upper pole isthe electrically conductive path between the main pole and the trailingmagnetic shield through the at least one second layer of theelectrically conductive portion.
 4. The magnetic head of claim 1,wherein: the magnetic head comprises a head which lacks a spin torqueoscillator stack; and the air bearing surface (ABS) of the magnetic headincludes planar surfaces of the main pole, the electrically conductiveportion, and the trailing magnetic shield.
 5. The magnetic head of claim4, wherein the electrically conductive portion contacts a trailingsidewall of the main pole and a leading sidewall of the trailingmagnetic shield in the trailing gap between the main pole and thetrailing magnetic shield.
 6. The magnetic head of claim 1, wherein theelectrically conductive portion contacts a trailing sidewall of the mainpole and a leading sidewall of the trailing magnetic shield in thetrailing gap between the main pole and the trailing magnetic shield. 7.The magnetic head of claim 5, wherein the at least one first layer ofthe electrically conductive portion comprises a copper, gold, platinum,ruthenium, chromium or tungsten layer which contacts the trailingsidewall of the main pole and the leading sidewall of the trailingmagnetic shield in the trailing gap between the main pole and thetrailing magnetic shield.
 8. The magnetic head of claim 1, wherein theat least one second layer of the electrically conductive portioncomprises an electrically conductive, magnetic layer, wherein theelectrically conductive portion contacts a trailing sidewall of the mainpole and a leading sidewall of the trailing magnetic shield in thetrailing gap between the main pole and the trailing magnetic shield. 9.The magnetic head of claim 1, further comprising an electrical coil thatis located adjacent to the main pole and configured to generate amagnetic flux through the main pole upon conduction of electricalcurrent through the electrical coil.
 10. A hard disk drive, comprising:the magnetic head of claim 9; a slider supporting the magnetic head; anactuator arm supporting the slider; a voice coil motor configured tocontrol the actuator arm; and a magnetic disk.
 11. A method of operatinga magnetic recording head comprising providing a current between a mainpole and an upper pole containing a trailing magnetic shield through anelectrically conductive portion located in a trailing gap between themain pole and the trailing magnetic shield while applying a magneticfield to the main pole from a coil to record data to a magnetic disk,wherein the electrically conductive portion is not part of a spin torqueoscillator stack, and the electrically conductive portion comprises atleast one electrically conductive, non-magnetic material layer, whereinthe electrically conductive, non-magnetic material portion is recessedfrom an air-bearing surface (ABS).
 12. The method of claim 11, wherein:the current is provided through a first electrical contact connecting aportion of the main pole distant from the air bearing surface toelectrical bias circuitry and a second electrical contact connecting aportion of the upper pole distant from the air bearing surface to theelectrical bias circuitry; an electrically insulating material layer islocated between the portions of the main pole and the upper pole distalfrom the air bearing surface; the electrically insulating material layerprovides physical and electrical isolation between the portions of themain pole and the upper pole distal from the air bearing surface; andthe current flows between the main pole and the upper pole only throughthe electrically conductive portion.
 13. The method of claim 11,wherein: the magnetic recording head comprises a head which lacks a spintorque oscillator stack; the air bearing surface (ABS) of the magneticrecording head includes planar surfaces of the main pole, theelectrically conductive portion, and the trailing magnetic shield; andthe current flows through an electrically conductive path which ispresent between the main pole and the upper pole through theelectrically conductive portion which contacts the main pole and thetrailing magnetic shield.
 14. The method claim 11, wherein theelectrically conductive portion contacts a trailing sidewall of the mainpole and a leading sidewall of the trailing magnetic shield in thetrailing gap between the main pole and the trailing magnetic shield. 15.The method of claim 14, wherein: the electrically conductive portioncomprises a single electrically conductive, non-magnetic material layer,a multilayer stack of electrically conductive, non-magnetic layers, or amultilayer stack of electrically conductive, magnetic and non-magneticlayers; and the electrically conductive portion contacts the trailingsidewall of the main pole and the leading sidewall of the trailingmagnetic shield in the trailing gap between the main pole and thetrailing magnetic shield.
 16. The method of claim 14, wherein theelectrically conductive portion comprises a copper gold, platinum,ruthenium, chromium or tungsten layer which contacts the trailingsidewall of the main pole and the leading sidewall of the trailingmagnetic shield in the trailing gap between the main pole and thetrailing magnetic shield.